WO2019165579A1

WO2019165579A1 - Elemental amorphous palladium, preparation method therefor and use thereof

Info

Publication number: WO2019165579A1
Application number: PCT/CN2018/077421
Authority: WO
Inventors: 何佳清; 何东升; 黄亦; 周毅
Original assignee: 南方科技大学
Priority date: 2018-02-27
Filing date: 2018-02-27
Publication date: 2019-09-06
Also published as: US11326229B2; US20200248282A1

Abstract

Provided are an elemental amorphous palladium, a preparation method therefor and a use thereof, the preparation method comprising: (1) loading an elemental palladium powder on a silicon nitride substrate; (2) heating the silicon nitride loaded with the elemental palladium powder obtained in step (1) to 800 to 1100 degrees Celsius and maintaining the temperature for at least 3 minutes; (3) cooling the palladium and silicon nitride system obtained in step (2) to room temperature at an apparent cooling rate of more than 103 degrees Celsius/second to obtain elemental amorphous palladium.

Description

Simple amorphous palladium and preparation method and use thereof

Technical field

The invention belongs to the field of amorphous materials, and in particular, the invention relates to elemental amorphous palladium and a preparation method and use thereof.

Background technique

The solid amorphous material is a condensed material with short-range order, long-range disorder and no defects inside. Conventional amorphous preparation methods mainly include liquid phase quenching and agglomeration from a diluted gaseous state. The liquid phase quenching method heats and melts the material mixture of the required components into a liquid state, and then rapidly cools them in a certain manner, so that the liquid disordered structure is preserved to form amorphous. Condensation from a dilute state means that atoms or ions in the material are dissociated in a gaseous form by different processes, and then they are rapidly and irregularly deposited on a cooling substrate to form an amorphous material.

In the field of amorphous materials, the preparation of pure elemental amorphous materials has been one of the most challenging problems in the field of materials and condensed matter physics. At present, the preparation method of elemental amorphous is mainly a quenching method. For example, Kim et al. found that spherical pure metal Fe droplets with a diameter of about 30 nm have a 50% probability of forming amorphous at a cooling rate of 10 ⁷ K s ^-1 , on the basis of which they consider body-centered cubic metal to face core. The cubic metal has a larger amorphous forming ability; moreover, it is more conducive to the formation of pure elemental metal amorphous by suppressing the formation of crystal nuclei or the growth of crystal nuclei when the melt is quenched. In addition, Angell et al. used a high-pressure quenching method to rapidly cool molten Ge at a high pressure of ～10 GPa to obtain elemental metal amorphous Ge. Mao et al. used a nanobridge device to build a metal Ta in a transmission electron microscope, and used nanosecond electric pulse method to melt the nano-Ta metal in the middle of the bridge into molten metal and cool it to amorphous at a cooling rate of 10 ¹⁴ K/s. In-situ observation of nano-pure metal amorphous preparation is realized.

Although the quenching method successfully prepared the corresponding amorphous state of body-centered cubic pure metals such as Ta, W, V, Mo, etc., this preparation method requires a high cooling rate and has certain requirements on the material size. Among the face-centered cubic pure metals, only Ni has been successfully prepared into amorphous. Therefore, the discovery of new elemental amorphous materials and the optimization of the preparation process of elemental amorphous are still difficult problems in the field of amorphous materials.

Summary of the invention

The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, an object of the present invention is to provide an elemental amorphous palladium and a preparation method and use thereof, which can prepare elemental amorphous palladium at a lower temperature decreasing rate, and prepare elemental amorphous palladium because The unity of the composition, without the complexity of multi-component metallic glass, can better guide the study of physical properties such as rheological properties, mechanical properties, electrical properties and thermal properties of metallic glass, and has high stability. . At the same time, amorphous palladium has a good application prospect in the fields of hydrogen storage and hydrogen separation membrane.

In one aspect of the invention, the invention provides a process for the preparation of elemental amorphous palladium. According to an embodiment of the invention, the method comprises:

(1) loading elemental palladium powder on a silicon nitride substrate;

(2) heating the silicon nitride loaded with the elemental palladium powder obtained in the step (1) to 800 to 1000 degrees Celsius and keeping it for at least 3 minutes;

(3) The palladium and silicon nitride systems obtained in the step (2) were cooled to room temperature at an apparent cooling rate of more than 10 ³ ° C / sec to obtain an elemental amorphous palladium.

The preparation method of the elemental amorphous palladium according to the embodiment of the present invention can prepare the elemental amorphous palladium at a lower temperature decreasing rate, and the prepared elemental amorphous palladium does not have the multicomponent metallic glass because of the unity of the composition. The complexity can better guide the study of physical properties such as rheological properties, mechanical properties, electrical properties and thermal properties of metallic glass, and has high stability. At the same time, amorphous palladium has a good application prospect in the fields of hydrogen storage and hydrogen separation membrane.

In addition, the method for preparing elemental amorphous palladium according to the above embodiment of the present invention may further have the following additional technical features:

In some embodiments of the present invention, in the step (1), the crystal structure of the elemental palladium powder is a face-centered cubic structure. Thus, it is possible to prepare an elemental amorphous palladium having higher stability by using metal palladium whose initial phase is face-centered cubic.

In some embodiments of the present invention, in step (2), the silicon nitride (Si ₃ N ₄ ) loaded with the elemental palladium powder obtained in the step (1) is heated to 800 degrees Celsius and kept for at least 3 minutes.

In still another aspect of the invention, the invention provides an elemental amorphous palladium. According to an embodiment of the present invention, the elemental amorphous palladium is prepared by the method described above. Therefore, the elemental amorphous palladium component is single, does not have the complexity of multi-component metallic glass, and can better provide guidance for the study of physical properties such as rheological properties, mechanical properties, electrical properties, and thermal properties of metallic glass, and It has high stability. At the same time, amorphous palladium has a good application prospect in the fields of hydrogen storage and hydrogen separation membrane.

In a third aspect of the invention, the invention provides the use of the elemental amorphous palladium described above for hydrogen storage or hydrogen separation.

The additional aspects and advantages of the invention will be set forth in part in the description which follows.

DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

1 is a schematic flow chart of a method for preparing elemental amorphous palladium according to an embodiment of the present invention;

2 is an electron micrograph of an elemental amorphous palladium obtained by a method for preparing elemental amorphous palladium according to an embodiment of the present invention.

Detailed description of the invention

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

In one aspect of the invention, the invention provides a process for the preparation of elemental amorphous palladium. According to an embodiment of the invention, referring to Figure 1, the method comprises:

S100: loading elemental palladium powder on a silicon nitride substrate

In this step, the elemental palladium powder may be commercially available or synthesized by physicochemical methods, and the crystal structure of the elemental palladium powder may be a face-centered cubic structure, for example, the face-centered cubic elemental palladium powder may be prepared by the following steps: It was obtained that 0.1050 g of PVP, 0.0600 g of citric acid, and 0.0600 g of L-ascorbic acid were dissolved in 8 mL of deionized water at room temperature, and the mixed aqueous solution was transferred to a three-necked flask and heated to 120 ° C for 5 min. Meanwhile, 0.0650 g of K ₂ PdCl ₄ was weighed and dissolved in 3 mL of deionized water at room temperature, and injected into a three-necked flask of a mixed aqueous solution at a rate of 360 mL/h, and reacted at 120 ° C for 3 hours to obtain a product using acetone. Rinse separately with deionized water to remove residual PVP, and obtain a monolithic palladium powder with a face-centered cubic structure. And the surface-centered cubic monocrystalline palladium powder is supported on the silicon nitride substrate by, for example, the following steps: mixing the elemental palladium powder with ethanol (C ₂ H ₅ OH) for ultrasonic dispersion, thereby obtaining a dispersion, The above dispersion was then supported on a silicon nitride (Si ₃ N ₄ ) substrate. Specifically, the above dispersion may be supported on a silicon nitride (Si ₃ N ₄ ) substrate by dropping. It should be noted that the mixing ratio of the elemental palladium powder to the ethanol (C ₂ H ₅ OH) and the ultrasonic dispersion time in the mixing process are not particularly limited, and those skilled in the art can select according to actual needs.

S200: heating the silicon nitride loaded with the elemental palladium powder obtained in step S100 to 800-1000 degrees Celsius and keeping it for at least 3 minutes.

In this step, the silicon nitride (Si ₃ N ₄ ) system loaded with the elemental palladium powder obtained in the above step S100 is heated to 800 to 1000 ° C and kept for at least 3 minutes. Specifically, at this temperature, the molten nano-palladium powder will be eutectic with the silicon of the silicon nitride substrate and held for a period of time such that the co-melt of palladium and silicon reaches an equilibrium state. According to an embodiment of the present invention, the silicon nitride loaded with the elemental palladium powder obtained in step S100 is preferably heated to 800 degrees Celsius and kept for at least 3 minutes.

S300: cooling the palladium and silicon nitride system obtained in step S200 to room temperature at an apparent cooling rate of more than 10 ³ degrees Celsius/second.

In this step, the palladium and silicon nitride systems obtained in the above step S200 are cooled to room temperature at an apparent cooling rate of more than 10 ³ degrees Celsius/second to obtain an elemental amorphous palladium. Specifically, the system is cooled at the cooling rate, and a sudden drop in temperature causes the silicon in the co-melt of the above palladium and silicon to precipitate first, and the elemental palladium is subsequently precipitated. Preferably, the palladium and silicon nitride system obtained in the above step S200 is cooled to room temperature at a cooling rate of 1100 ° C / sec.

At the same time, the present invention has the following advantages compared with the prior art:

A new type of elemental amorphous palladium was prepared by heating/cooling method. The initial phase of the elemental amorphous phase is face-centered cubic metal palladium. The amorphous state of this metal has not been reported in the literature before.

2. The cooling rate of conventional amorphous preparation tends to be high. The amorphous palladium of the present invention can be formed by cooling at an apparent cooling rate of 1000 ° C / s, the cooling rate is much lower than the reported values, and the amorphous palladium is prepared. Has a high stability.

3. The elemental amorphous palladium of the present application can be used for hydrogen storage or hydrogen separation membrane technology.

In still another aspect of the invention, the invention provides an elemental amorphous palladium. According to an embodiment of the present invention, the elemental amorphous palladium is prepared by the method described above. Therefore, the elemental amorphous palladium component is single, does not have the complexity of multi-component metallic glass, and can better provide guidance for the study of physical properties such as rheological properties, mechanical properties, electrical properties, and thermal properties of metallic glass, and It has high stability. At the same time, amorphous palladium has a good application prospect in the fields of hydrogen storage and hydrogen separation membrane. It should be noted that the features and advantages described above for the preparation method of the elemental amorphous palladium are also applicable to the elemental amorphous palladium, which will not be described herein.

In a third aspect of the invention, the invention provides the use of the elemental amorphous palladium described above for hydrogen storage or hydrogen separation. Specifically, elemental amorphous palladium can be used in hydrogen storage or hydrogen separation membrane technology. It should be noted that the above-mentioned features and advantages described for the elemental amorphous palladium are also applicable to the use of the elemental amorphous palladium in hydrogen storage or hydrogen separation, and are not described herein again.

The invention is described below with reference to the specific embodiments, which are intended to be illustrative, and not to limit the invention in any way.

Example

0.1050 g of PVP, 0.0600 g of citric acid, and 0.0600 g of L-ascorbic acid were dissolved in 8 mL of deionized water at room temperature, and the mixed aqueous solution was transferred to a three-necked flask and heated to 120 ° C for 5 min. Meanwhile, 0.0650 g of K ₂ PdCl ₄ was weighed and dissolved in 3 mL of deionized water at room temperature, and injected into a three-necked flask of a mixed aqueous solution at a rate of 360 mL/h, and reacted at 120 ° C for 3 hours to obtain a product using acetone. Rinse with deionized water separately, remove residual PVP, and obtain a face-centered cubic metal elemental palladium powder; then, the obtained elemental palladium powder is mixed with ethanol and ultrasonically dispersed for 15 minutes to obtain a dispersion, and then the liquid droplets are taken by a pipetting gun. On the NanoEx-iv MEMS chip produced by Thermo Fisher Company; the sample was heated to 800 ° C and kept for 5 min, then rapidly cooled to room temperature at a temperature drop rate of 1100 ° C / s to obtain elemental amorphous palladium. The electron micrograph is shown in Figure 2. Show.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solutions of the present invention within the scope of the technical idea of the present invention. These simple variants All fall within the scope of protection of the present invention.

It should be further noted that the specific technical features described in the above specific embodiments may be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention has various possibilities. The combination method will not be described separately.

In addition, any combination of various embodiments of the invention may be made as long as it does not deviate from the idea of the invention, and it should be regarded as the disclosure of the invention.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

A method for preparing elemental amorphous palladium, comprising:

(1) loading elemental palladium powder on a silicon nitride substrate;

(2) heating the silicon nitride loaded with the elemental palladium powder obtained in the step (1) to 800 to 1000 degrees Celsius and keeping it for at least 3 minutes;

(3) The palladium and silicon nitride systems obtained in the step (2) were cooled to room temperature at an apparent cooling rate of more than 10 3 ° C / sec to obtain an elemental amorphous palladium.
The method according to claim 1, wherein in the step (1), the crystal structure of the elemental palladium powder is a face-centered cubic structure.
The method according to claim 1 or 2, wherein in the step (2), the silicon nitride loaded with the elemental palladium powder obtained in the step (1) is heated to 800 degrees Celsius and kept for at least 3 minutes.
An elemental amorphous palladium characterized in that the elemental amorphous palladium is produced by the method according to any one of claims 1-3.
Use of the elemental amorphous palladium according to claim 4 for hydrogen storage or hydrogen separation.